The present invention relates to the manufacture of concrete paving blocks for erecting retaining walls, and in particular, to the creation of selectively shaped retaining walls made from a plurality of such blocks.
Retaining walls are necessary to secure soil embankments adjacent roadways, streets, rail lines etc. from sliding or giving way as a result of rain or other shifts in terrain. Traditionally, such walls have been constructed from concrete, bricks, wood ties and other similar materials piled or erected to form a wall behind which earth is back filled. With the ability of molding and casting concrete paving blocks, rather inexpensively, a number of improved retaining wall systems have been suggested.
An example of a retaining wall using block elements is shown in U.S. Pat. No. 4,825,619 to Forsberg. In this patent, there is disclosed the formation of blocks that can be placed side by side and stacked on top of each other to form a wall of multiple courses. Each of the blocks is provided with holes that allow pins to be driven through the block into corresponding holes in the block of the underlying course. In this manner, subsequent courses are secured to preceding ones as the wall is erected. This type of construction requires significant on-site labor, careful alignment of the blocks as well as the securing of each block element with the aforementioned pins.
The aforementioned patent is just one of series of patents obtained by Mr. Forsberg, each seemingly depicting a differ facial design and overall shape, but each requiring pins in order to obtain the necessary interlocking of the stacked blocks. Reference can be made to design Pat. Nos. D.300,253; D.311,444 and D.298,463.
The individual blocks are cast in modular form generally using a conventional block molding machine. After casting and curing, the blocks are bundled, wrapped and piled on shipping pallets for storage and ultimate transport to the project site. It has been found that the conventional blocks are difficult to strap and palletize and require excess handling. Moreover, the stacking, palleting and transporting of the known blocks are difficult and costly, requiring excessive care to see that the blocks do not shift in travel.
In addition to the difficulty in interlocking and stacking blocks, the individual blocks such as those of Forsberg lack versatility in the creation of pleasing arrangements of retaining wall designs. For example, notwithstanding the large number of design patents, Forsberg cannot erect a retaining wall having an arc radius of less than 20 feet. Thus, the retaining walls erected by Forsberg are essentially straight walls. Secondly, the step-back of a Forsberg retaining wall is severely limited and steep sloped walls are almost impossible.
It is an object of the present invention to provide a concrete block for erecting retaining walls overcoming the disadvantage of the prior art blocks.
It is, therefore, the object of the present invention to provide a concrete block that can be easily stacked to form a secure retaining wall with minimal labor and cost.
It is a further object to provide a wall block that can be stacked as to form a straight, circular or stepped-back walls.
It is a further object of the present invention to provide a wall block that can be easily stacked and secured for shipping.
These objects, together with other objects and advantages, will be apparent from the following disclosure of the present invention.